G'day everyone,
I have a Husky ride-on with Briggs 20 hp engine on it, 2016 model 40N877 in the workshop. It hunts from idle through to top no load revs. I have changed the plugs, removed and clean out the carby btw it was clean inside no debris or blocked holes(Nikki single throat carby). I checked to see if there was a sheared key in the keyway but that was fine, it has fresh fuel in it and there is no blockage in the filter and the fuel pump pumps fuel. Spark is good from both coils jumped across my spark tester nice blue spark. But one thing I noticed when I gave it a compression test, right hand cylinder had 100psi but left hand cylinder had 150psi, I tested both cylinders twice and got the same readings engine oil is still clean and at proper level.I also pulled the connector block off the back of the press button start assembly, cleaned all the contacts with contact cleaner. So after doing all these things it stills hunts while running, I have both Briggs V Twin engine workshop manuals but they don't do this one, the carby linkage set up is different to the older V twin set up this only single throat carby not dual throat. So I don't know if Briggs have brought out a updated workshop manual? So any help or suggestions from fellow small mechanics please let me know or if someone has come across the problem I have described please let me know how you fixed the problem. cheers Mike